1. Field of the Invention
The present invention concerns a method of adjusting (taring) or re-calibrating, respectively, an apparatus having a flexible pre-tensioned liquid-filled tube, sealed at one of its ends and connected to a pressure sensor at its other end. A differential of an external pressure exerted onto the tube by a person and a previous pressure prevailing in the tube is uses for activating predetermined controlling functions
2. Discussion of Background Information
Application of flexible tubes of generally described above are known from the patent literature that includes: EP 1 216 911, EP-1621442 as well as the Swiss Patent Application Nr. 0952/07 filed on Jun. 14, 2007.
The above-noted apparatus has been utilized in combination with the steering mechanism of self-propelling vehicles (e.g., a steering wheel of an automobile, a handlebar of a motorcycle, etc.) and/or as a sensor incorporated into a seat of a vehicle. The first mentioned case makes use of the instinctive reaction of the driver in the event of stress situation such as an unexpected appearance of an obstacle that requires immediate braking action, and/or the reaction to an optical or acoustic signal. In this regard, the instinctive grasping grip on the steering wheel or on the handle bar is effected by the driver within a very short time span, but without activating the acoustic alarm signal device arranged at the centre of the steering wheel, e.g., the vehicle horn, which can only be reached slowly and which might cause injuries to the hand, e.g., in the event the air bag pops up. In the second mentioned case, reliable detection of the presence of a person (children, adults, etc.) on the passenger seat and/or measuring of the person's body weight in the seat is achieved in order to control activation of the air bag associated with the seat. In this way, in case of an accident, the intensity of the air bag blowing-up can be adapted in such a manner that un-necessary activation of the air bag is avoided and body injuries can be caused by the popping of the air bag can be limited, even if the air bag in many cases can save the lives of persons involved in an accident. Statistics prove that air bags popping indiscriminately can cause serious injuries to, e.g., children, people wearing glasses, etc. Thus, it is important that such an event can be advantageously controlled, even if it occurs very rarely.